A two-deck trailer is advantageous as it provides more floorspace to enable more products to be carried, and for many products the payload is increased by up to 65%. However, such a trailer is more difficult to load 15 than a conventional trailer.
Modern warehouses have a floor level which is about the same height as a trailer floor, for example about 1200 mm above ground level. The loading dock may be a platform built outside the building to the same level as the internal floor, or it may be an opening in the wall of the building against which the rear of the trailer is reversed for loading or unloading.
To load a trailer with two fixed floors from a loading dock requires that the trailer is fitted with a lift gate to lower the product from the upper floor to the level of the loading dock and vice versa, or else to be loaded by a forklift or similar away from the loading dock.
Alternatively, an internal lift may be fitted allowing the trailer to be reversed against the loading dock but this means that the inward depth of the lift platform must be sacrificed from the rear of the upper fixed floor thereby losing load space.
If the lift gate is fitted externally then the trailer must be parked away from the loading dock by at least the length of the platform and is not desirable because it allows hot or cold outside air into the warehouse and also exposes the goods and the operating personnel to the weather.
Trailers with an upper floor capable of being raised and lowered by screw jacks or hydraulic rams are also known. This allows the trailer to carry variable height loads on the upper or lower floor but the same difficulties exist when loading or unloading both floors at a loading dock.
It is an object of this invention to provide an improved construction of goods vehicle.